Process for the phase separation spinning of yarns from fiber-forming polyparaphenylene oxides



United States Patent ""ice U.S. Cl. 264203 3 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a process for the spinning of yarns from polyphenylene ethers, and more particularly poly 2,6 dimethylparaphenylene ether, by extruding a liquid consisting of a mixture of the polymer and an auxiliary material through a spinning orifice into a medium in which the liquid is formed into a thread.

BACKGROUND OF THE INVENTION Field of the invention The present invention lies in the field of spinning yarn from a polymeric material in a novel manner and in such a way as to bring about new and unexpected results.

Description of the prior art A process of this general character is already known from British Patent No. 930,993 to which reference may be made for further details.

SUMMARY OF THE INVENTION It has been found according to the present invention that the process of the kind referred to above is with advantage carried out in a particular way. Accordingly, the process according to the present invention is char acterized in that the auxiliary material is homogeneously miscible with the polymer at the spinning temperature, but is immiscible with the polymer at the temperature of the medium into which the liquid is extruded.

The yarns obtained by the process according to the present invention have properties which make them particularly suitable for use in textiles. Moreover, this process makes it possible to achieve spinning speeds that cannot, or can only with great difficulty, be realized in the usual spinning processes.

The yarns obtained by the process according to the present invention are strong and supple, they have a very attractive subdued luster which is strongly suggestive of that of natural silk, and the woven and knitted fabrics that are manufactured from said yarns may be washed in water of a high temperature (for instance, 100 0), without the fabric being subject to a high degree of creasing. The yarns have a porous structure.

The manner in which the thread is formed in the process according to the present invention is entirely different from that used in melt spinning, dry spinning or wet spinning.

In the melt spinning process a thread is formed as a result of the molten polymer being cooled after it has emerged from the spinning orifice, so that it solidifies. This method can be used for the melt spinning of polyphenylene oxides on a laboratory scale, but it has so far not been found practicable for use in the melt spinning of these polymers on an industrial scale.

In the dry spinning process a thread is formed as a result of the solvent which is employed being evap- Patented Nov. 4, 1969 orated after the polymer has left the spinning orifice, so that the polymer, which still contains some amount of solvent then, forms into a solid thread. Since the amount of solvent to be evaporated is large, the spinning speed is limited by the speed at which the amount of heat required for said evaporation can be supplied.

In the wet spinning process the spinning liquid is extruded through the spinning orifice into a coagulating liquid in which the polymer coagulates owing to the coagulating bath extracting the solvent fromthe polymer solution.

In the process according to the present invention, however, the thread is formed in such fashion that after the liquid has left the spinning orifice, the auxiliary material is not miscible with the polymer at the temperature of the medium in which the thread formation is to take place. The auxiliary material then separates from the polymer, which consequently solidifies.

Suitable auxiliary materials are p-dichlorobenzene, naphthalene and 3,5-xylenol. However, since very good results are obtained with lactams, their use is preferred. Suitable lactams are pyrrolidone, capryl lactam, dodecanolactam and N-substituted lactams such as methyl, ethyl, phenyl, naphthyl and stearoyl lactams. Since caprolactam is readily available and gives excellent results, this compound is the preferred lactam. The auxiliary material may consist of a mixture of compounds.

The auxiliary material may separate from the polymer in the liquid state or in the solid state. Depending on the nature and the amount of the separated auxiliary material and the purpose for which the spun thread is to be used, the thread may be subjected to an aftertreatment to partly or completely remove the auxiliary material. This may be done by evaporating the auxiliary material at a suitable temperature and pressure, or by extracting it from the thread with the aid of a washing liquid which is preferably heated.

In order to improve the mechanical and physical properties of the spun thread it is preferably subjected to a single or multi-stage drawing process. This drawing process may be carried out at room temperature, but it is preferably carried out at an elevated temperature. A particularly favorable range of temperatures is from 180 to 270 C.

Drawing may take place before the auxiliary material has been removed, but it is as a rule facilitated if the thread no longer contains any auxiliary substance, so that it is preferred to carry out the drawing process after the auxiliary material has been removed. However, it is also possible to carry out the drawing process while the auxiliary material is being extracted.

The amount in which the auxiliary material is present in the spinning liquid may vary between wide limits. The amount must not be so small that after the spinning liquid has left the orifice, the auxiliary material remains homogenously mixed with the polymer. On the other hand, there is no point in employing an amount greater than is necessary for a satisfactorily operative spinning process. For most auxiliary materials the optimum amount will be between 60 and by weight, calculated on the amount of spinning liquid.

Although the process according to the present invention is suitable for spinning polyphenylene oxides in general, it is more particularly suitable for spinning poly-2,6-dimethylparaphenyleneoxide, which will hereinafter be referred to as PPO. Although the present invention will be further described with reference to spinning with PPO, it is by no means limited thereto; the other polyphenylene oxides mentioned in British Patent No. 930,993, may be made into threads by this same process.

In addition to the polymer and the above-mentioned auxiliary materials the spinning liquid may contain sub stances which need not form a homogeneous mixture with the spinning liquid. Examples of such substances are pigments, dyestuffs, heat and/or light stabilizers, softening agents, color-improving agents and other substances that may if desired to readily incorporated in the polymers used in the preparation of synthetic fibers. Or PPO may be mixed with other polymers such as polystyrene, which may be added in an amount up to 60% by weight of the total amount of polymer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order still better to illustrate the nature of the present invention the following detailed examples are set forth, it being understood, however, that this description and these examples are presented here by way of illustration only and not as limiting the scope of the invention.

Examples After the Washed thread has been dried, it is in a number of cases subjected to a drawing process under conditions also indicated in the table.

The viscosity of the PPO is the relative viscosity measured on a 1% by weight solution in benzene at 30 C.

The tensile strength before drawing is measured after the caprolactam has been washed out.

While specific examples of preferred methods embodying the present invention have been set forth above, it will be understood that many changes and modifications may be made in the methods of procedure without departing from the spirit of the invention. It will therefore be understood that the examples cited and the particular proportions and methods of operation set forth above are intended to be illustrative only, and are not intended to limit the scope of the invention.

What is claimed is:

1. In a process for the spinning of fibers of poly-2,6- dimethylparaphenylene oxide by extruding a hot spinning solution of the said polymer through a spinning orifice and cooling the spinning solution when leaving the spinning orifice to form fibers, the improvement characterized in that the spinning solution comprises the said polymer and caprolactam as a solvent.

2. A process according to claim 1, wherein the solvent is present in an amount of 90% by weight, calculated on the amount of spinning solution.

3. A process according to claim 1, wherein after the formation of the fibers the solvent is removed by washmg.

Composition of spinning liquid Tensile Caprostrength Tensile PPO, lactam, Withstrength Elonpercent percent spinneret Extrusion drawing undrawn Drawing of drawn gation Vise by by Others, percent temp., speed, speed, thread, Draw temp., thread, at

PPO Weight weight by weight C. m1./min. m./min. g./tex. ratio C. g./tex. break 3. 2 17 83 150 12 3.2 17 8 (toluene) 150 12 3. 2 20 160 12 3. 2 20 80 160 12 3. 2 19 81 6 3.2 19 81 9. 6 3.2 19 80 1 (methanol). 150 12 3.2 19 80 1 (weter) 12 3.2 19 1 12 3. 2 19 137 12 3. 2 17 160 12 2. 0 25 120 12 2.0 25 120 12 2. O 26 120 12 2.0 26 120 12 2. 0 30 125 12 2. 0 30 125 12 2. 0 35 140 12 References Cited UNITED STATES PATENTS 2,695,835 11/1954 Hare 264182 2,820,770 1/1958 Adams 26078 X 2,824,780 2/ 1958 Satterthwaite. 2,953,818 9/1960 Bartron 264-203 X 2,965,437 12/1960 Blomberg 264-184 2,996,474 8/ 1961 Voigt. 3,029,226 4/ 1962 Kessler et al. 3,037,956 6/1962 Kessler et al. 3,221,080 11/1965 Fox. 3,342,892 9/1967 Laakso 260823 3,356,761 12/1967 Fox 260874 3,373,226 3/1968 Gowan 260874 OTHER REFERENCES Condensed Chem. Dictionary by Rose et al., 6th ed. Reinhold Pub. Co., p. 213, 1965, Gr. 146, A.D.5C5,

JULIUS FROME, Primary Examiner J. H. WOO, Assistant Examiner U.S. Cl. X.R. 

